1. Field of the Invention
The present invention relates to a jaw crusher for breaking a non-rigid object like asphalt. More particularly, the present invention relates to a jaw crusher suitable for breaking a viscous, non-rigid object, e.g., asphalt pavement wastes.
2. Description of the Background Art
Jaw crushers are known and used as machines for breaking rocks, asphalt pavement wastes, concrete scraps, etc. into pieces of desired size. These days, a large amount of concrete scrap and asphalt pavement waste are produced by dismantling of concrete buildings, repair of asphalt pavements, etc. Treatment of these wastes, particularly in urban areas, gives rise to a social problem because of the generation of noise and dust during the treatment, difficulty in securing a place for dumping wastes, a high cost of waste transportation, etc. For this reason, these wastes are desired to be speedily treated and reused at or near the site where the wastes are produced, as much as possible.
It will be advantageous if asphalt pavement wastes can be broken into pieces which are sufficiently small in particle size to be reused as aggregates or other similar material by using a conventional jaw crusher capable of efficiently breaking a rigid object, e.g., rocks, into pieces of desired size. However, if a conventional jaw crusher, which has been developed to break rocks or other rigid objects since the beginning of the development thereof, is used for breaking asphalt pavement wastes as it is, the asphalt pavement wastes may be undesirably mashed or stick to the movable and fixed tooth plates and fail to drop from the V-shaped crushing space defined between the two tooth plates. Thus, the conventional jaw crusher becomes unable to break the object of crushing. Moreover, it is almost impossible for the conventional machine to crush asphalt pavement wastes favorably for reuse of them. At present, conventional jaw crushers are reluctantly used as they are for breaking asphalt pavement wastes, and reuse of asphalt pavement wastes is not considered.
Incidentally, jaw crushers for breaking rocks include various types which may be most suitably selected for each particular use in conformity to the kind of rock to be crushed and the particle size of pieces into which rocks are to be broken. We carried out an experiment by breaking asphalt pavement wastes with these various types of conventional jaw crusher, and found a new way of improving the conventional jaw crushers for effectively breaking asphalt pavement wastes.